1. Field of the Invention
The present invention relates to an image display apparatus, such as a head mount display (“HMD”), which includes an observation optical system configured to present one combined image by combining light fluxes from a plurality of display elements.
2. Description of the Related Art
The HMD needs a small observation optical system configured to lead an image at a wide angle to an exit pupil (eyeball), and a variety of structures for downsizing the optical unit corresponding to each display element are conventionally proposed with a plurality of display elements.
For example, Japanese Patent Laid-Open No. (“JP”) 2009-115906 discloses an image display apparatus that piles two optical elements each including three display elements and three optical units. JP 2010-266787 discloses an image display apparatus that includes an observation optical system that enables light fluxes from a plurality of images to the same image have an overlap in the exit pupil, and an image display apparatus having an overlap area configured to display the same image and partially provided to the plurality of display elements.
It is difficult for JP 2009-115906 to observe a smooth and continuous image because an image gets chipped near the boundary when the eyeball rotates. In this case, it is conceivable to apply the method disclosed in JP 2010-266787 to prevent the image from getting chipped near the boundary when the eyeball rotates, but according to both JP 2009-115906 and JP 2010-266787, a slope angle of each of the plurality of display elements is different from each other and the HMD is likely to have a large size.